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प्रश्न
Give reason for the following:
The lower block of a block and tackle pulley system must be of negligible weight
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उत्तर
The lower block pulleys should be as light as possible to maximise efficiency, and lubricants should be used to reduce friction in pulley bearings.
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संबंधित प्रश्न
A boy uses a single fixed pulley to lift a load of 50 kgf to some height. Another boy uses a single movable pulley to lift the same load to the same height. Compare the effort applied by them. Give a reason to support your answer.
Answer the following in short.
Explain the various functions that a machine can perform.
Give reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
The mechanical advantage of an ideal single movable pulley is ______.
Give a reason for the following:
In a single fixed pulley, the velocity ratio is always more than the mechanical advantage.
Name a machine which is used to:
change the direction of force applied.
State two reasons, why the efficiency of a pulley system is not 100 percent?
What is the relation between the mechanical advantage and the number of strands of string used to support the load, in a ‘block and tackle’ set-up?
A pulley system has a velocity ratio of 4 and an efficiency of 90%. Calculate:
(i) the mechanical advantage of the system.
(ii) the effort required to raise a load of 300 N by the system.
_______ is a machine made up of wheel and rope.
